well it's nto very well explaimed, is it, and often the audeicne don't care enough - jsut think it;s stupid

I agree. The explanation of what exactly went on was poor. It can seem (and this has been the case for some of my friends) to some movie-goers that in GoF one person tortured Neville's parents and then in OotP it was another. It can get confusing. Only people who have read the books will understand.